Neuro Anatomy 4 - Cranial Nerves Flashcards
Which aspect of the brain are the cranial nerves visible on?
Ventral aspect
Which of the cranial nerves are sensory alone?
Olfactory (CN I)
Optic (CN II)
Vestibukocochlear (CN VIII)
Which of the cranial nerves are motor alone?
Oculomotor (CN III) Trochlear (CN IV) Abducens (CN VI) Spinal Accessory (CN XI) Hypoglossal (CN XII)
Which cranial nerves are mixed?
Trigeminal (CN V)
Facial (CN VII)
Glossopharyngeal (CN IX)
Vagus (CN X)
Where does the olfactory nerve (CN I) enter the CNS?
Many tiny nerves which hang off the olfactory bulb
Where does the optic nerve (CN II) enter the CNS?
At the optic chiasm
Where does the oculomotor nerve (CN III) originate?
Anterior aspect of the midbrain
Where does the trochlear nerve (CN IV) originate?
Posterior aspect of the midbrain
Name of the nerve that can be seen as a large root at the lateral aspect of the pons?
Trigeminal nerve
Which 3 cranial nerves emerge from the pontomedullary junction from medial to lateral?
Abducens (CN VI), Facial (CN VII), vestibulocochlear (CN VIII)
Which 3 cranial nerves emerge from the lateral aspect of the medulla from anterior to posterior?
Glossopharngeal (CN IX)
Vagus (CN X)
Spinal Accessory (CN XI)
Which cranial nerve emerges from the medial aspect of the medulla?
CN XII (hypoglossal)
What direction do all the cranial nerves exit from the brain?
what are the 2 exceptions to this rule?
Anteriorly
CN IV = posteriorly
CN VIII = laterally
What are cranial nerve nuclei?
Places were the CNs synapse before moving out/ coming into deeper parts of the brain
What are the names of the groups of efferent nerve cells that send their axons into cranial nerves?
Motor nuclei
What are the names for the groups of nerve cells upon which the sensory neurones of the cranial nerves synapse?
Sensory nuclei
Where are the soma of the sensory nerve cells of cranial nerves found?
In ganglia outside of the CNS
What is the only sensory modality that does not synapse in the thalamus prior to reaching the cortex?
Olfactory nerve (CN I)
What is the cranial nerve nuclei name for the olfactory nerve?
Olfactory bulb
Where is the primary olfactory area in the brain located?
Medial aspect of the temporal lobe
What do the olfactory nerves pass through before synapsing with the olfactory bulb?
Cribriform plate
What do action potentials pass along between the olfactory bulb and primary olfactory area?
Olfactory tract
In the brainstem, how are the sensory and motor regions situated in comparison with each other?
Motor regions = medial
Sensory regions = lateral
What is the name for the small swellings in the roof of the midbrain involved in vision and hearing?
Colliculus
what part of the brainstem is the nucleus for CN III located?
Upper Midbrain
What part of the brainstem is the nucleus for CN IV located?
Lower Midbrain
What part of the brainstem is the nucleus for CN VI located?
Mid Pons
What part of the brainstem is the nucleus for CN XII located?
Lower pons to medulla
What are the name of the nuclei for the oculomotor nerve (CN III)?
What nerve modality leaves from each?
Edinger-Westphal nucleus (parasympathetic to spincter pupillae) Oculomotor nucelus (somatic motor to levator p.s., ST, MR, IR, IO)
What is the name of the nuclei for the trochlear nerve (CN IV)?
Which nerve modality leaves from it?
Trochlear nucleus
Somatic motor to superior oblique
What is the name of the nucleus for the abducens nerve (CN VI)?
Which nerve modality leaves from it?
Abducens nucelus
Somatic motor
What is the name of the nucleus for the hypoglossal nerve (CN VII)?
Which nerve modality leaves from it?
Hypoglossal nucleus
Somatic motor to geniog., hyog., stylog., intrinsic muscles of the tongue
Where are the nuclei for the spinal accessory nerve located?
Medulla
Cervical spinal cord
What are the name of the nuclei for the spinal accessory nerve?
Spinal accessory nucleus (from cervical spinal cord) Nucleus ambigus (from medulla)
Functions of CN V (trigeminal nerve)?
Somatosensation of the face
Proprioception associated with chewing
Motor controls to muscles of mastication, tensor tympani, mylohyoid, anterior belly of digastric, tensor veli palatini
What are the 3 sensory trigeminal nuclei?
Mesencephalic nucleus
Pontine trigmeninal nucleus (principle nucleus)
Spinal nucleus
What signals are carried to the mesencephalic nucleus?
Proprioception info from chewing
What signals are carried to the pontine trigeminal nucleus?
Discriminative touch, vibration
What signals are carried to the spinal nucleus?
Pain, temp
Which is it important that the mesencephalic nucleus is very close to the motor nucleus?
Jaw reflexes- proprioceptive information from teeth and jaw arrive at the mesencephalic nucleus - prevents you biting tongue for example
Where are sensory nuclei for the trigeminal nerve located?
Stretches as one continues nucleus from the midbrain down to the upper 2 segments of the cervical spinal cord
What is the name of the tract which carries information from the trigeminal sensory nuclei to the cortex?
Ventral trigeminothalamic tract
Do the fibres of the ventral trigeminothalamic tract cross the midline?
What does this mean?
Most do but some don’t = bilateral representation of touch, vibration in cortex
What are the 3 functions of the facial nerve (CN VII)?
Motor to muscles of facial expression, strapedius
Parasympathetic innvervation to pterygopalatine and submandibular ganglia
Taste to anterior 2/3 of tongue (via C. tympani)
What are the 4 functions of the glossopharyngeal nerve (CN IX)?
Tactile sense, pain and temperature sense from the posterior tongue, pharyngotympanic tube and upper pharynx
Taste (posterior 1/3 of tongue)
Parasympathetic fibres to the otic ganglion (parotid gland)
Motor (stylopharyngeus)
4 functions of the vagus nerve (CN X)?
Tactile sense, pain and temperature sense from the pharynx, trachea, oesophagus and thoracic and abdominal viscera
Taste (epiglottis)
Parasympathetic innervation to ganglia serving thoracic and abdominal viscera
Motor (striated muscle of the pharynx and larynx) (cranial accessory contributes to this function)
What are the 4 nuclei for the facial nerve?
Facial motor nucleus
Salivatory nucleus
Solitary nucleus
Spinal nucleus
Where are the nuclei associated with the facial nerve located?
Caudal pons
What information travels from the facial motor nucleus?
Motor to muscles of facial expression
What information travels from the salivary nucleus?
Parasymapthetic innervation to the submandibular and pterygopalatine ganglion
What information is transmitted to the solitary nucleus?
Taste from the anterior 2/3rds of the tongue
What information is transmitted to the spinal trigeminal nucleus?
Small region of somatosensation associated with the ear
What are the 4 nuclei associated with the glossopharyngeal nerve?
Solitary nucleus
Spinal nucleus
Nucleus ambiguus
Inferior salivatory nucelus
Where are the nuclei associated with the glossopharyngeal nerve located?
upper medulla
What information does the solitary nucleus collect?
Taste
What information does the spinal trigeminal nucleus collect?
Small region of somatosensation associated with the ear
What information is transmitted from the inferior salutatory nucleus?
Parasympathetic to the parotid gland
What information is transmitted from the nucleus ambiguus?
Motor
What are the 4 nuclei associated with the vagus nerve?
Dorsal (Motor) nucleus
Solitary nucleus
Spinal trigeminal nucleus
Nucleus ambiguus
Where are the 4 nuclei associated with the vagus nerve located?
Upper medulla
In relation to the vagus nerve, what information is transmitted to the spinal trigmeninal nucleus?
Pain from dura and small region of somatosensation associated with the ear
Which cranial nerves share the solitary nucleus?
CNs VII, IX, C
What information do the cranial nerves transmit to the solitary nucleus?
Taste and visceral sensory information
What cranial nerves share the superior and inferior salivary nuclei?
CNs VII, IX
What information is transmitted to the cranial nerves to the superior and inferior salivary nuclei?
Parasympathetic efferents to ganglia of salivary glands and pterygopalatine ganglion
What cranial nerves share the nucleus ambiguus?
CNs IX and X (and cranial part of XI)
What information are transmitted from the nucleus ambiguus?
Motor efferents to muscles of pharynx, larynx and upper oesophagus
What are the 2 parts of the solitary nucleus?
What kind of signal does each receive?
Gustatory nucleus (taste) Commissural nucleus (visceral afferents)
Where is the solitary nucleus located?
Extends in a V shape from upper to lower medulla
Name for the part of the pyramidal tract that is motor to cranial nerves?
Corticobulbar tract
What cranial nerves does the corticobulbar tract contain fibres for?
CNs V, VII, X, XII
Which cranial nerves contain parasympathetic efferents?
CN III, VII, IX, X
What structure is the main influence of input to the CNs containing parasympathetic efferents?
Hypothalamus
What is the reticular formation?
A network of loosely aggregated cells with cell bodies, axons and dendrites intermingling in the central core of the brainstem